1. Field of the Invention
The present invention relates to an object detecting method provided to detect a predetermined object such as a foot passenger from an image picked up through an image pickup device and an apparatus therefor.
2. Description of the Related Art
In recent years, the installation of monitoring cameras in shops for the sake of security has become widespread rapidly. Further, it has been proposed that the above-described cameras should be used for not only acquiring video, but automatically counting the number of people going in and out of a shop and/or people passing near the shop so that data obtained through the camera can be used for a marketing research of the shop.
A technology of counting foot passengers existing in a predetermined area from video data acquired through a camera has been disclosed in Japanese Patent Laid-Open No. 4-199487. According to the above-described document, a camera 2 is installed above a passage so that the camera 2 points directly below, as shown in FIG. 2. Since the shape of the head of a person 1 viewed from the camera 2 installed above is a circle, a person can be detected and counted by extracting data of a circular object from video data obtained through the camera 2.
On the other hand, in the recent years, technologies for detecting face data from image data by using the technologies proposed in the following documents, that is, Rowley et al, “Neural network-based face detection”, IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE, VOL. 20, NO. 1, Jan. 1998, and Viola and Jones, “Rapid Object Detection using Boosted Cascade of Simple Features”, Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition (CVPR'01) have become commercially practical. The use of the above-described technologies allows for installing a camera 4 forward of a passage as shown in FIG. 3 and detecting face data from video data obtained through the camera 4 so that a person 3 can be counted.
However, for counting people, a pattern of the identification target varies according to whether a camera installed on the ceiling is used to count people passing directly below the camera or a camera installed at the side of a passage is used to count people crossing the field of vision. Therefore, identification functions used to perform the people counting also vary. Accordingly, contrary to expectations, where the camera should be installed has been restricted depending on identification functions implemented on a system.